低应变法检测既有基桩时上部结构的影响及消除方法研究  

Study on superstructure effect and elimination method of low strain method for detecting existing piles

作　　者：徐教宇 韩超 任国家 Xu Jiaoyu;Han Chao;Ren Guojia(China Academy of Building Research,Beijing 100013,China;National Center for Quality Supervision and Test of Building Engineering,Beijing 100013,China)

机构地区：[1]中国建筑科学研究院有限公司,北京100013 [2]国家建筑工程质量监督检验中心,北京100013

出　　处：《建筑科学》2020年第11期56-64,共9页Building Science

基　　金：住房和城乡建设部研究开发项目(K22015036)资助。

摘　　要：采用三维有限元研究了上部结构对基桩中扭转波和纵波的反射规律,当上部结构尺寸满足一定的条件时,上部结构对基桩中扭转波的反射可近似为固定端的反射;研究既有基桩采用低应变检测时,上部结构对基桩的激励及缺陷反射的影响,根据弹性一维杆波动理论,提出采用一种去除上部结构影响的方法,从而能够消除上部结构的影响,提高了既有基桩检测的准确性。采用模型桩及工程实例进行了研究验证,结果表明该理论和方法的准确性、可靠性及实用性,对于既有基桩完整性检测有重要的意义。The three-dimensional finite element method is used to study the reflection law of the superstructure on torsional and longitudinal waves.When the size of the superstructure meets certain conditions,the reflection of torsional wave from the superstructure to the pile can be approximated to that from the fixed end.This paper studies the influence of superstructure on the excitation and defect reflection of existing piles when low strain testing is used.According to the elastic one-dimensional bar wave theory,a method is proposed to remove the influence of superstructure,which can eliminate the influence of superstructure and improve the accuracy of detection of existing piles.Model piles and engineering examples are used to verify the theory and method.The results show that the theory and method are accurate,reliable and practical.It is of great significance for the integrity testing of existing foundation piles.

关 键 词：低应变 既有桩基检测 桩身完整性 纵波 扭转波 反射 上部结构 

分 类 号：TU473.16[建筑科学—结构工程]